The Organic Light Emitting Diodes (OLED) display device possesses many outstanding properties of self-illumination, low driving voltage, high luminescence efficiency, short response time, high clarity and contrast, near 180° view angle, wide range of working temperature, applicability of flexible display and large scale full color display. The OLED is considered as the most potential display device.
The OLED can be categorized as Passive matrix OLED (PMOLED) and (Active matrix OLED) AMOLED according to their driving types. The AMOLED comprises pixels arranged in array and belongs to active display type, which has high lighting efficiency and is generally utilized for the large scale display devices of high resolution.
FIG. 1 is a structure diagram of an OLED display device according to prior art. As shown in FIG. 1, the OLED display device comprises: an OLED substrate 600 and a package cover plate 700 located on the OLED substrate 600; the OLED substrate 600 generally comprises: a substrate 100, a plurality of anodes 200 separately located on the substrate 100; a pixel definition layer (PDL) 300 located on the substrate 100 and the plurality of anodes 200, a plurality of spacers 500 located on the pixel definition layer 300, a plurality of openings 310 being located on the pixel definition layer 300 and respectively corresponding to the plurality of anodes 200, and a Hole Injection Layer 410, a Hole Transporting Layer 420, an organic light emitting layer 430, an Electron Transport Layer 440, an Electron Injection Layer 450 and a cathode 460 which are sequentially stacked up from bottom to top in the plurality of openings 310 and on the cathodes 200; the package cover plate 700 contacts the plurality of spacers 500 on the OLED substrate 600.
Specifically, the cathodes 200, the Hole Injection Layer 410, the Hole Transporting Layer 420, the organic light emitting layer 430, the Electron Transport Layer 440, the Electron Injection Layer 450 and the cathode 460 which are sequentially stacked up from bottom to top construct an OLED element, together. The OLED element generally uses ITO and metal to respectively be the anode 200 and the cathode 460 of the element. Under the driving of a certain voltage, the electrons and the holes are respectively injected into the Electron Transport Layer 440 and the Hole Transporting Layer 420 from the cathode 460 and the anode 200. The electrons and the holes migrate from the Electron Transport Layer 440 and Hole Transporting Layer 420 to the organic light emitting layer 430 and bump into each other in the organic light emitting layer 430 to form excitons to excite the emitting molecules. The latters can illuminate after the radiative relaxation.
Specifically, in the production process of the OLED substrate 600, the manufacture process of the substrate 100, the anodes 200 and the pixel definition layer 300 is generally named to be the TFT manufacture process. The following manufacture process of the Hole Injection Layer 410, the Hole Transporting Layer 420, the organic light emitting layer 430, the Electron Transport Layer 440, the Electron Injection Layer 450 and the cathode 460 is named to be the OLED manufacture process. Because the substrate size of the OLED manufacture process is generally smaller than the substrate size of the TFT manufacture process, it is necessary to cut the accomplished substrate of the TFT manufacture process (the carrier is generally the glass) before the OLED manufacture process. The knife flywheel is used for cutting in general, and because the glass debris generated by the cutting will cause the damage to the OLED element, a photoresist (PR) layer 800 (as shown in FIG. 2) is generally coated on the surface of the accomplished substrate of the TFT manufacture process before cutting. After cutting, the photoresist layer 800 is stripped. Because the photoresist material, i.e. the same material of the photoresist layer 800, is also commonly used for manufacture the pixel definition layer 300, is can be easy to cause the wrong stripping of the pixel definition layer 300 in the stripping process of the photoresist layer 800, and after the following film structure of the Hole Injection Layer 410, the Hole Transporting Layer 420, the organic light emitting layer 430, the Electron Transport Layer 440, the Electron Injection Layer 450 and the cathode 460 is formed, it will lead to the loss of the pixel definition layer 300 for protecting the plurality of anodes 200 and the short circuit among them, and thus lead to the failure of the OLED element.
Meanwhile, as shown in FIG. 3, in the OLED manufacture process, the evaporation processes for the structure layers of the Hole Injection Layer 410, the Hole Transporting Layer 420, the organic light emitting layer 430, the Electron Transport Layer 440, the Electron Injection Layer 450 and the cathode 460 need to use the FMM (Fine Metal Mask) 900. Because the stability of the photoresist material used for the pixel definition layer 300 is not strong, and is extremely volatilized onto the fine metal mask 900 to cause the pollution of the fine metal mask 900. Accordingly, the clean frequency of the fine metal mask 900 is increased, and the usage efficiency is decreased to raise the production cost.